Though much of the app remains under wraps, it will solve the annoying problem of having to use an iPhone to follow workout instructions, Well+Good notes.

Customers will also get instructions on their watches, and they'll be able to see their heart rate and the actual calories they're burning, so they'll know just how hard they're actually working.

Itsines' app, Sweat with Kayla, already earned more this year than any other fitness app, including Under Armour's My Fitness Pal app, Bloomberg Businessweek reported.

Itsines rose to Instagram fame with her original PDF-guides— which required looking at photos and using a timer — called Bikini Body Guides. She told Bloomberg Businessweek she regrets calling it that, which is why she named her app Sweat with Kayla.

"Do I regret calling my guides Bikini Body? My answer is yes," she said to Bloomberg Businessweek. "That's why when I released the app, I called it Sweat With Kayla. Sweat is so empowering. I love that."

Itsines has amassed a massive following; she has 5.5 million followers on Instagram, largely due to how she posts dramatic transformations from her #BBG girls, or "Kayla's Army."